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Discussion Starter #1
HI Im building a subwoofer box and need help determining port length.
The Box is 2.188 Ft^3 and will have 2 round 3 inch PVC port.
The ports will stick out of the box 5 1/4 inches
I want to tune it tune 32Hz (is this good for rap and EDM?)
My question is A port calculator website gave me a port length of 14.81 inches

Does this include the 5 1/4 inches that extrude?

Is the 14.81 inches for each port or would each be half of that?

I'm using a 45 degree elbow how do i calculate the volume of that?

Thanks so much



 

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32 is a decent tune...you could raise it a little if needed.

the part that sticks out of the box is included in the length...but only the part inside the box deducts from the overall airspace in the box.

meaning that if you need to build a ported box that is say 2 cut ft ...toy need to build it so the air space equals 2 cu ft plus whatever the port and the driver take up.

Second, if it says you need a 3" port, 20 inches long, you CAN'T do 2 3" ports 10 inches long...it doesn't work like that. You need to find a port calculator that will factor in 2 ports.

As for elbows...there is info online as to how to measure that.


Any reason why you chose do do a pair of 3" ports?
 

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Discussion Starter #3
Wow that was quick thanks. I tried yahoo answers and no reply for days so I decided to make an account and ask the pros :)

Anyways so i make (2) 14.81 inch long port tubes correct?

I'm using dual 3 inch because it will penetrate into the cabin (pics below). It seemed right not to small not to big.



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It looks like the program allowed you to enter "2" for amount of ports. So it would appear to me that they are telling you that yes you need 2 ports 14.81" long each.

Are you sure you need elbows? i would think that with 5.25 outside the box...that would leave only 8" inside the box...your box is 14" tall...thats plenty of room to do straight ports.
 

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Discussion Starter #6
honestly i was trying to copy this
12" Subwoofer Box Enclosure for BMW E30 (1983-1992) - German Audio Specialties

I know the guy who designed it knows what he is doing and has years of experience the box also has amazing reviews on the forums. I tired to copy it (with his permission) and figured there was a reason for the 2 ports so i didn't question it.

plus i already made the holes :(
 

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honestly i was trying to copy this
12" Subwoofer Box Enclosure for BMW E30 (1983-1992) - German Audio Specialties

I know the guy who designed it knows what he is doing and has years of experience the box also has amazing reviews on the forums. I tired to copy it (with his permission) and figured there was a reason for the 2 ports so i didn't question it.

plus i already made the holes :(
cool...thats all good, but why the elbows? Generally the only reason to add 45 degree bends in a port is when you have no choice. You can just go straight down and be done. elbows just complicate things.
 
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